Question: When did Charles Lyell hold the position of  President of the Geological Society of London?
Paraphrase: When was Charles Lyell President of the Geological Society of London?
SPARQL (Wikidata): SELECT ?value WHERE { wd:Q5333 p:P39 ?s . ?s ps:P39 wd:Q7241336 . ?s pq:P580 ?value}